Reversible temperature switch



'Feb 2, `1932. M E, HENNING 1,843,601

l REVERSIBLE TEMPERATURE SWITCH Filed Oct. 9, 1930 2 Sheets-Sheet l Feb. 2, 1932. M E, HENNlNG 1,843,601

` REVERSIBLE TEMPERATURE SWITCH Filed 0G13. 9, 1950 2 Sheets-Sheet 2 v ff E? 4 W UPPLY Z SUPPLY `Patented Feb. 2, 1932 UNITED `STATES PATENT OFFICE MALCOLM E. HENNING, OF :DES MOINES, IOWA, ASSGNOB. TO PENN ELECTRIC SW'ITCH i COMPANY, OF DES MOINES, OWA, A CORPORATION F IOWA REVERSIBLE TEMPEATURE SWITCH Application led October 9, 19301. Serial No. 487,49E.

An object of my invention is to provide a reversible temperature switch or similaicontrol mechanism which may be adapted Jfor controlling electric circuits of motors or the like, the switch being of the temperature responsive type and being of simple, durable and inexpensive construction. y

Another object of my present invention is to provide a switch in which the actuating mechanism is so connected with the control mechanism that it is possible to, by a simple adjustment, adapt the device for either opening at high temperature and closing at low temperature or vlce versa. f

Still a further object is to provide a switch structure having a temperature responsive elementcontrolling a .rotatable rod, the rod having an arm on it for engaging spaced stops mounted on a plate, the plate itself controlling the rotation of a cam and the camoperating a control mechanism such as a circuit switch.

Still a further object is to provide the stops Iand cam arranged so that there is a projection on the cam arranged in a predetermined position with respect to the stops and there is a depression on the cam located so that the cam and stops can be changed relative to each other so that the depression will correspond to the same position with'respect to the stops that the projection did whereby a temperature scale, used in connection with the stops, may be used for either setting of the cam and the cam when in one `position will open the switch at a predetermined temperature and in the other position wil-l cause reverse or closing action of the switch at the'same tem-- perature. Thus the device is adaptable lfor opposite types of circuit controls, such as for oil burner motors and air circulating motors used in connection with a furnace, which require opposite operation with respect to the temperature of the furnace jacket. .(5

Still a further object is to provide a cam having a depression and a projection engageable with a control mechanism and each circumferentially elongated whereby after moving the control mechanism to one of its positions or the other, the cam can continue te rotate without imparting any additional movement to the control mechanism.

1With these and other objects in View my invention consists in the construction, arrangement and combination of the various parts or" my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure l is a front elevation of my reversible temperature switch showing the cover plate on the switch box removed and the device mounted in a chimney wall or the like with part of the temperature responsive thermostatic element broken away to conserve space on the drawings.

F igure 2 is an enlarged sectional View on the line 2 2 of Figure l showing the depression of the cam coacting with the control mechanism.

Figure 3. is a similar view showing the projection of the cam coacting with the control mechanism.

F iguret is a sectional view on the line 4 4 of Figure 2.

Figure 5 is an end elevation of the graduated plate, stops and actuating arm, as viewed from the left side ot Figure l.

Figure 6 is a sectional View on the line 6 6 of Figure et showing the connection between the graduated plate and the cam sleeve. i l

Figure 7 is a sectional view similar to a portion of Figure 4 showing the parts separated forl changing the. adjustment of the device.

Figure 8 is an electrical diagrammatic view showing the switch connected with an oil burner blower motor and Figure 9 is an electrical diagrammatic view showing my switch connected" with an air circulating :tan of a furnace.

@n the accompanying drawings, li have 'used the reference numeral l() to indicate a switch casing. A cover for the casinfg erably as a meansof connection between the casing 10 and the box 14. A damper plate 2() is pivotally mounted bymeans of va rivet 22P on the damper box 14. The damper plate is provided with damper openings 24 and a cover'plate 26 of the box 14l is provided with damper openings 28.

A tubular sleeve-like extension 30 extends from the damper box 14 and is adapted to be inserted through a furnace jacket or the like (see Figure 1). The extension 30 may be supported relative to the jacket 32 by ears 33 and bolts 35. The sleeve 30 terminates in a hub 34 through which a rod 36 is rotatably mounted. Air openings 38 afford communication between the interior of the `damper box 14 and the interior of the jacket 32.

The circulation of air in the jacket causes a suction of air through the damper openings 24 of the damper plate 20 and the damper openings 28 of the cover plate 26 and then through the openings 38 so that the parts over which the air travels may be kept comparatively cool.

The inner end of the rod 36 is connected by a screw 40 to one end of a temperature responsive element 42 preferablyof the bimetallic coil type. The other end of the elev ment 42 is stationarily anchored by means of a screw 44 whereby ytemperature changes actin upon the element 42 will twist it and there rotate the rod 36, which serves as an actuating means for the control mechanism hereinafter to be described.

The rod 36 extends through'the sleeve 16 and then loosely through a cam sleeve 46 which is rotatably mountedwith respect to the switch casing 10. On the outer end of the ro 36 an actuating arm 48 is screw threadey ly mounted and is held in any desired position to which it is adjusted by means of a lock nut 50. The actuating arm 48 is adapted to travel bet-Ween and engagem spaced stops 52 and 54. The stops 52 and 54 are rotatable relative to a graduated plate 56 and are retained thereagainst by a lock nut 58. The stops 52 and'V 54 are provided with prongs 60 adapted to engage in notches 62 formed around the periphery of the plate 56 whereby to positively maintain the stops in any position towhich they are adjusted.

The graduated plate 56 is provided with an opening 64 of a shape other than circular, which is adapted to engage a similarly shaped shoulder 66 of the cam sleeve 46. These parts are given a shape other than circular so that the graduated plate 56 can be assembled in only two positions with respect to a cam 68, which is mounted on and secured to the cam sleeve 46. l

As shown in Figure 7, the lock nut 58 can be loosened so that the plate 56 can be disengaged from the shoulder 66 and the cam 68 rotated to the other position after which the For imparting movement to the switch arm 70, a bell crank shaped control lever 86 is provided having arms 88 and 90. The control .lever 86 is pivotally mounted on the pin 72 so that the arm 88 thereof is adapted' to engage the cam 68 and the arm 90 to engage the switch arm 70. A magnet 92 is provided which acts upon the switch arm 70 kto constrain the arm 88 of the lever 86 toward engagement with the cam 68 and which also has a dampening effect on an arc formed between the contacts 74 and 76 when the switch arm 70 is moved to open circuit position. The magnet 92 also constrains the switch arm 70 toward closing movement and maintains the contacts 74 and 76 in-tight engagement with each other when the cam 68 allows the switch arm to remain in closed circuit position.

The cam 68 is provided with a circumferentiallly' elongated projection 94 and a circumferentially elongated depression 96. The shoulders 98 which occur between the transition from projection to depression have a definite location with'respect to each other as will hereinafter be described.

Practical operation of my reversible temperature switch 1. In connection with a device requiring an open circuit when the telnperature is high.

Referring to Figure 8, my switch is connected in series with an oil burner blower motor 100 and a room thermostat 104. A hot air furnace is indicated at 114 into which the oil and air from the blower motorfan is discharged.

Assuming that the room -thermostat 104 calls for heat, it will be in closed circuit position and my reversible temperature switch,

which I will refer to generally by the reference character A, will also be in closed position because of the furnace jacket 32 of the furnace 114 being cold. The fire will then burn for raising the' temperature in the room and the switch A will open the circuit when y the temperature in the jacket 32 reaches the predetermined degree at which the stop 54 is set. This operation occurs because of an unwinding of the thermostatic element 42, which rotates the rod 36 and causes the actuating arm 48 to .engage the stop 54. This causes rotation of the cam from the position shown in Figure 2 to the position shown in Figure 3, for instance, which presses downwardly on the arm 88 and moves the switch arm 70 to open circuit position.

After open circuit position is reached, the cam may continue'to rotate as shown in Figure 3, but will not impart any additional movement to the switch arm, because of the projection 94 of the cam 68 being circumferentially elongated.

IVhen the temperature in the jacket 32 lowers, the actuating arm 48 will swing from the stop 54 and finally engage the stop 52 at the predetermined temperature for which this stop is set whereupon the switch .4t will be closed and if the thermostat 104 still calls for heat, the motor 100 will again be .energlzed.

When the switch is used as just described, it is strictly a high temperature limit switch and is usually adjusted for opening at about 300 degrees Fahrenheit.

2. In connection with a device requiring a closed circuit when the temperature is high.

In Figure 9, I have diagrammatically illustrated a hot air furnace with the temperature responsive element 42 of the switch A mounted inside the furnace jacket 32. At low temperature, the switch is open so that the fan will, not operate and thereby force cold air into the room and at high temperature thc switch is closed for causing operation of the fan 112 and consequent circulation oit hot air. When the switch is used as just 'de-4 scribed, it is a control switch constituting the sole means for making and breaking the fan circuit instead of being a limit switch and connected with another control switch. such as the room thermostat 104, when used in the installation shown in Figure 8.

In an installation of this type, the parts are loosened as shown in Figure 7 and the caln 68 given a! half turn relative to the plate 56 and then the parts reassembled by screwing the lock nut 58 down against the stop 52. AThe cam will then assume theposition shown by dotted linesI in Figures 2 and 3 or will be reversed so that the same temperature scale setting on the plate 56 can be used in connection with the stops 52 and 54, but the operation ofthe switch would be reversed.

Since the plate 56 when adjusted to this position is turned just a half turn with respect to its other adjustment, it will be ob- .vious that the shoulders 98 of the cam 68 must be exactly opposite each other in order to make the scale readings on the plate 56 accurate for both adjustments of the switch.

I have provided a switch which can be readily and accurately changed for open circuit operation at high temperatures and vice versa, as will be obvious from the drawingsl and description of my invention. Other advantages are inherent in the invention as hereinbefore set forth.

Various changes can behiade in the construction and arrangement of the parts of the switch and the device can be used for controlling" devices other than those disclosed without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as myyinvention:

1. In a device yoit' the class described, a temperature responsive element, a rotatable rod operatively connected therewith, a cam loose on said rod and having a pair oi stops, an arm on said rod engageable with said stops for rotating said cam from said rod and a control mechanism movable to opera tive and inoperative positions and operatively engageable with said cam for actuation therefrom.

2. In a device of the class described, a temperature responsive element, a rotatablerod operatively connected therewith, a cam loose on said rod and having a pair of stops, an arm on said rod engageable with said stops for rotating said cam from said rod, a oo ntrol mechanism movable to operative and inoperative posit-ions and operatively engageable with said cam and magnetic means to cause such operative engagement.

3. In a device of the lclass described, a temperature responsive element, a rotatable rod operatively connected therewith, a cam loose on said rod and having a pair of stops, an arm on said rod engageable with said stops .for rotating said cam from said rod, a controlmechanism movable to operative and inoperative positions and operatively engaging said cam and means to reverse said cam relative to said stops for causing reverse operation of said -control mechanism.

4. In a device of the class described, an actuating mechanism, a cam associated therewith, a control mechanism operable from said cam and means for reversing the association of said cam with respect to said actuating mechanism.

5. In a device of the class described, a tem perature responsive element, a rotatable rod operatively connected therewith, a cam on said rod and operatively connected therewith, a control mechanism movable to operative and inoperative positions and operatively engaging said cam and means to reverse said cam relative to said rod.

6. In a device of the class described a temperature responsive element, a rotatable rod operatively connected therewith, a cam loose on said rod, a plate detachably associated with said cam and capable of adjustment to two different positions relative thereto, means operatively connecting said rod and said plate together, a control mechanism movable to operative and inoperative positions and operatively engaging said cam, said cam having a projection corresponding with a predetermined point on said plate when thev plate is in one of said positions and having a depression corresponding to the same polnt when said plate is in its other position.

7. In a device of the class described, a temperature responsive element, a rotatable rod operatively connected therewith, a cam loose on said rod, a plate attached to said cam, means whereby said plate can be attached in only two positions relative thereto, a projection on said cam corresponding to a predetermined point on said plate when the plate is in one of said positions, a depression corresponding to the same point when the plate is in the other of said positions and control mechanism operated by said cam.

8. In a device of the class described, a temperature responsive element, a rotatable rod operatively connected therewith, a cam loose on said rod, a plate attached to said cam, means whereby said plate can be attached in only two positions relative thereto, a projection on said cam corresponding to a predetermined point on said plate when the plate is in one of said positions, a depression corresponding to the same point when the plate is in the other of said positions. and control mechanism operated'by said cam, said cony trol mechanism comprising a switch arm,

contacts, one of which is stationary and the other movable with the switch arm and a magnet. v

9. In av device of the class described, a temperature responsive element, a rotatable rod operatively connected therewith, a cam loosev on said rod, a platel attached to said cam, means whereby said plate can be attached in only two positions relative thereto, a projection on said cam corres onding to a predeter- 45. mined point on said p ate when the plate is in one of'said positions, a depression corresponding to the same point when the plate is in the other of said positions and control mechanism operated by said cam, said control mechanism comprising a switch arm, contacts,

one of whichis stationary and the other mov- -able with the swinh arm and magnet exertmovement thereto when the cam continues to rotate. l

11. In a device of the class described a temperature responsiveelement, a rotatable rod operatively connected therewith, a cam on said rod andvoperatively connected therewith, a control mechanism movable to operative' and inoperative positions and operatively engaging said cam, said cam having a circumferentially elongated projection and a circumferentially elongated depression which; after moving the control mechanism from one position to another, do not impart additional movement thereto when the cam continues to rotate.

12. In a device of the class described, a temperature responsive element, a rotatable rod operatively connected therewith, a cam 0n said rod and operatively connected therewith, a control mechanism movable to operative and inoperative positions and operaconstraining said control mechanism toward `engagement with said cam.

13. In a device of the class described, an

anism operable by said cam and spaced stop and arm mechanism for providing an operative connection between the actuating mechanism and the cam.

14. In a device of the class described, an actuating mechanism, a cam associated therewith, a control mechanism operable by said cam and engageable therewith, magnetic means for causing such engagement and means for adjusting the vposition of the cam whereby to vary the operation of said control mechanism.

15. In a device of the class described, an actuating mechanism, a cam associated therewith, a control mechanism operable by said cam and engageable therewith, magnetic means for causing such engagement, said control ymechanism including circuit contacts located in the field of said magnetic means. 16. In a device ofthe class described, a. temperature responsive element, a rotatable rod operatively connected therewith, a cam on said rod and a control mechanism operable by said cam, means for adjusting the position of said cam whereby to vary the operation of said control mechanism.

Des Moines, Iowa, Au st 23, 1930.

MALCOLM E. HENNING. 

